The present invention generally relates to an apparatus and processes for drying and for heating various materials. More particularly, the present invention relates to a pulse combustion apparatus and process for drying slurries and to a pulse combustion apparatus and process for providing heat to a process heater.
Pulse combustors are useful in a wide variety of applications. A pulse combustor is a device generally having a combustion chamber that is adapted to receive fuel and air. The fuel and air are mixed in the combustion chamber and periodically self-ignited to create a high energy pulsating flow of combustion products and an acoustic pressure wave. Typically, the pulse combustor also includes one or more elongated resonance tubes associated with the combustion chamber for achieving release of the hot gases from the chamber on a periodic basis. The pulsating flow of combustion products produced can be used for a variety of purposes.
For instance, the assignee of the present invention has developed a variety of systems and processes incorporating a pulse combustor. Some of these processes and systems are disclosed in U.S. Pat. No. 5,059,404 entitled "Indirectly Heated Thermochemical Reactor Apparatus And Processes," U.S. Pat. No. 5,211,704 entitled "Process And Apparatus For Heating Fluid Employing A Pulse Combustor," U.S. Pat. No. 5,255,634 entitled "Pulsed Atmospheric Fluidized Bed Combustor Apparatus," and U.S. Pat. No. 5,353,721 entitled "Pulse Combusted Acoustic Agglomeration Apparatus And Process," all of which are specifically incorporated herewith by reference thereto in their entireties.
The present invention is generally directed to an apparatus containing a pulse combustion device that can be used as part of a drying system or as part of a heating system. In a drying arrangement, a stream of materials is directly contacted with a flow of combustion products emanating from a pulse combustor. The combustion products cause moisture and any other volatile liquids to evaporate for recovering a solids product contained within the material stream. When used as a heating system, on the other hand, the combustion products originating from the pulse combustor are fed to a heat exchanger where heat transfer occurs.
In the past, others have attempted to use a pulse combustor for drying various feed streams. For instance, U.S. Pat. No. 5,252,061 to Ozer et al. discloses a pulse combustion drying system. The system includes a pulse combustor and an associated combustion chamber whereby a pulsating flow of hot gases are generated. A tailpipe is connected to the outlet of the combustion chamber, a material introduction chamber is connected at the outlet of the tailpipe, and a drying chamber is connected at the outlet of the material introduction chamber. The system further includes cooling means for controlling the temperature of the hot gases issuing from the outlet of the tailpipe.
In U.S. Pat. No. 5,092,766 to Kubotani, a pulse combustion method and pulse combustor are disclosed. The pulse combustor includes a combustion chamber, an air intake with an open end, an exhaust pipe, and a fuel port and an ignition means. The pulse combustor further includes a compressed gas supplying means disposed at a position opposing to the open end of the air intake so that a stream of compressed gas jetted from the gas supplying means is blown into the combustion chamber through the open end of the air intake. A heat insulating cover encloses the pulse combustor so as to form an annular space between them, which receives a part of the compressed gas jetted from the compressed gas supplying means.
A pulse combustion energy system is disclosed in U.S. Pat. No. 4,992,043 to Lockwood, Jr. The system functions to recover a solid material which has been in suspension or solution in a fluid. In one embodiment, a pulse combustor is coupled to a processing tube which in turn is coupled to a pair of cyclone collectors. Material to be processed is fed into an upstream end of the processing tube and the resulting processed material is removed from the combustion stream by the cyclone collectors.
Other prior art references directed to drying systems using pulse combustors include U.S. Pat. No. 5,136,793 to Kubotani, U.S. Pat. No. 4,701,126 to Gray et al., U.S. Pat. No. 4,695,248 to Gray, and U.S. Pat. No. 4,637,794 to Gray et al.
Although the prior art discloses various systems and processes incorporating a pulse combustor, various features and aspects of the present invention remain absent. In particular, the present invention provides further advancements and improvements in pulse combustion heating and drying systems.